CVE-2026-40706

Local root escalation via malformed ACL entries

Published Apr 21, 2026 · Updated Apr 21, 2026

Heap buffer overflow in NTFS-3G 2022.10.3 before 2026.2.25 allows local users to gain root privileges via a crafted NTFS image. ntfs_build_permissions_posix() writes attacker-derived POSIX_ACE entries beyond its heap allocation while translating multiple denied WRITE_OWNER entries from distinct group SIDs. Exploitation requires the SUID-root binary to process the image with POSIX ACL support and user mapping active, permitting corruption of adjacent heap metadata.

CVSS severity8.4
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in NTFS-3G 2022.10.3 before 2026.2.25 allows local users to gain root privileges via a crafted NTFS image. ntfs_build_permissions_posix() writes attacker-derived POSIX_ACE entries beyond its heap allocation while translating multiple denied WRITE_OWNER entries from distinct group SIDs. Exploitation requires the SUID-root binary to process the image with POSIX ACL support and user mapping active, permitting corruption of adjacent heap metadata.

The record

CVE
CVE-2026-40706
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
Tuxera
Product
NTFS-3G
Classifications
CWE-122, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2022.10.3 <2026.2.25

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Tuxera · NTFS-3Gversion=2022.10.3 <2026.2.25

Published CVSS scores

8.4MITRECVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8TuxeraCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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